More than 40 years after astronauts first walked on the moon, the U.S. space program is in search of direction. With the end of the space shuttle program last year, the United States must rely on Russian Soyuz rockets to send Americans into space. Private contractors are building spacecraft to ferry astronauts to the International Space Station and beyond, but those won't be ready for years. Meanwhile, budget cutters have pared NASA spending, and President Obama has angered some space enthusiasts by proposing to shift funds from two international Mars missions to a new telescope slated to replace the aging Hubble observatory. Mars remains a tantalizing destination, and a sophisticated rover is scheduled to land there in August to search for signs of life. But a human landing may be decades away. Obama has rejected returning to the moon as a stepping stone to Mars, preferring to send astronauts to an asteroid.